1. A confidence intervalfor a population meanhas a margin of error of 10.7. What is the length of the confidence interval?

2. A random sampleof size 17 is taken from a population. A normal probabilityplot of the sample datais found to be very close to linear. The population standard deviationis unknown. The appropriate method for obtaining the confidence interval is the z-interval procedure. Is this true?

3. A variable of a population has a mean of 266, and a standard deviation of 16… Ten observations of this variable have a mean of 262.1 and a sample standard deviation of 20.4. The observed value of the standardized version of x-bar is z =-.77, and the studentized version of x-bar is t = -0.605. Is this true? Show answers.

1. A confidence interval for a population mean has a margin of error of 10.7. What is the length of the confidence interval?

As we know that a confidence interval is equal to

(sample mean -margin of error, sample mean + margin of error)

Hence, the length of the confidence interval is equal to

2*margin of error.

If a confidence interval for a population mean has a …

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